Tuesday, March 22, 2016

Those bunnies interested in
sausage making would be advised to read the extended discussions between the referees and the authors of the Hansen, et al paper on potentially catastrophic anthropic climate change, at the bottom of the
ACP discussion page. Eli will lead off with the discussion of the title of the paper. As to why read this stuff, well Stoat has put it clearly, who will read the paper and tell us what it is about. The answer is the editor and referees, and if you read the discussion, much of the work has been done for you. That and the video on the previous post.

Frank Raes (R2) starts this off by commenting

The authors ostensibly cross boarders when it comes to describing the
possible consequences of the papers results. In the discussion, many
have argued that the use of words like “highly dangerous” in the title,
and the adding of a (shallow) discussion regarding ethics, justice and
prescribing policy action might be out of the scope for a disciplinary
natural sciences journal like ACP.

I want to be clear from the beginning. I strongly believe that a
collective issue such as climate change can no longer be discussed in
scientific terms only, but that the scientific discourse must inform, or
even go along ethical and political discourses. There is indeed a role
for scientists to engage in the latter discourses, based on the former.
However, my point is that there are many other ways to engage in these
discourses and to have the voice of science heard. (The first author has
made use of these other means frequently and successfully in the past).
Putting the full scientific, ethical, juridical, and policy
prescriptive discussion in an ACP paper is, in my opinion, not only
totally ineffective, but it may put also a good disciplinary journal
into problems. It is something for the ACP editors to consider, but
gain, there are other means. I will make a suggestion later for ACP for
how deal with this with respect to the current paper.

3. My comments and suggestions to ACP are as follows.

3.1 Title

The title presently use by the authors is rather journalistic. That
would be OK if the paper would also be written in a journalistic (but
correct) way. It isn’t. It is a complex 50 pages long technical paper
that even scientists are struggling with. It is too much to hope for
that journalists would read it, including all the caveats it contains.

If the ACP editors would like to keep the title to the standards of a
disciplinary paper, and stick to what the paper is really about, the
title should, in my opinion, be more like:Non-linear Ice Melt, Multi-meter Sea Level Rise and Superstorms at 2°C
Global Warming: clues from Paleoclimate Data, Climate Modeling, and
Modern Observations.
That is already a strong enough title, covering the content of a strong piece of science.

However, in the climate change debate, the term “dangerous” has been
given a rather precise definition in Art 2 of he UNFCCC, namely a change
that doesn’t allow ecosystems to adapt, that threatens food production
and that prevents economic development in a sustainable manner. It is
obvious that a multi-meter sea-level rise within a century would be
“dangerous” in that sense, at least in low-lying islands and coastal
areas.

I could therefore also live with a title that reads.

Ice Melt, Sea Level Rise and Superstorms: Evidence from Paleoclimate
Data, Climate Modeling, and Modern Observations that 2°C Global Warming
is “Dangerous”.
Where the quotes indicate that a special meaning is given to
“Dangerous”. A reference could be made to UNFCCC in the abstract, and a
fuller explanation in the body of the text.

Given the many uncertainties and need for further analyses mentioned by
the authors themselves and by reviewers in the Discussion, one should
however argue for the following title:

Ice Melt, Sea Level Rise and Superstorms: Evidence from Paleoclimate
Data, Climate Modeling, and Modern Observations that 2°C Global Warming
could be “Dangerous”.

Peter Thorne, (D2?, no R3) who was the least happy with the polemical components of the
original paper, was still not thrilled as reflected by his comments on
the title:

The title needs changing to
reflect that the outcome is inherently uncertain if I am to be able to
recommend acceptance. The easiest solution would be to insert
Potentially before Highly Dangerous that would provide some sense of the
uncertainty in the underlying analysis. More substantial changes would
be along the lines of ‘Exploring potential impacts of a 2C world using
insights from paleo climate records, modern observations and climate
modelling’ or ‘Exploring the potential for tipping points in the
climate system before 2C’. Basically, I think the title needs to reflect
that the outcome is not deterministic and not guaranteed , even if we
are foolish enough to stay on a carbon intensive pathway.

Both
the abstract and the conclusions need to make clear that the evidence
cannot rule out large - scale changes but that, equally, it is not a
given that such changes shall occur. They need to better reflect that
there remain substantial uncertainties and areas where further research
is required to make definitive conclusions. Such revisions would be
consistent with the underlying text and reflect the true state of
scientific knowledge in the area.

The editor in charge of the paper relays this information to Hansen and the reply of the authors extends this

You mention that referees R3 and R4 question the title of the paper. The issues raised about the title concern the word “Dangerous” in the title, and they are important because they get at the very heart of our paper and the overall topic of human - made climate change. I think that the discussions raised are pertinent and I am glad that you give us the chance to propose a title and show that it is well motivated.
I believe that you may have misread the relevant comment of R4. R4 notes that a major goal of our paper is to define “dangerous anthropogenic interference”, and he then quotes the 1992 United Nations Framework Convention on Climate Change (UNFCCC), as follows

“...to achieve, in accordance with the relevant provisions of the Convention, stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.”

R4 then says that our paper: “...significantly advances this quest for a more quantified definition of such human impact. Very few serious efforts have been made to arrive at a useful definition of ‘dangerous anthropogenic interference’. Previous efforts focused on sea level rise have been less rigorous, I believe, with less analysis of the coupling of ice meltwater with oceanic dynamics.”

R4 does not mention the paper’s title or criticize it, but explicitly recommends publication of the paper. R3, on the other hand, does criticize the title and does so by referring to the UNFCCC, but his reference is not correct. The word “dangerous” appears once and only once in the UNFCCC, namely in the most fundamental phrase of the Convention, which is given in the inset phrase above. R3 says that “...in the climate change debate, the term ‘dangerous’ has been given a rather precise definition in Art 2 of the UNFCCC, namely a change that doesn’t allow ecosystems to adapt, that threatens the food production and that prevents economic development in a sustainable manner”. This is a rephrasing of Article 2 that seems to slightly change its meaning. Let us look at Article 2 in its entirety:

The ultimate objective of this Convention and any related legal instruments that the Conference of the Parties may adopt is to achieve, in accordance with the relevant provisions of the Convention, stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. Such a level should be achieved within a time frame sufficient to allow ecosystem s to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner.

Article 2 thus uses the word “dangerous” with regard to the level of greenhouse gases in the atmosphere. The ecosystems/food/economics sentence refers to timeframe in which that level should be obtained. The word “dangerous” is not further defined, perhaps because it is assumed to be well understood.

R2 suggested “potentially dangerous” (probably you meant to refer to R2, rather than R4), but that is too weak. That conclusion already could have been reached without any of the research in our paper.

There is an important issue at play here: overall, it seems to me that the relevant scientific commun ity has been exercising self - censorship in its warning to the public about the danger of human - made climate change. It would be difficult to overstate the threat of increasing human - made climate change, which we suggest threatens to bring about some of th e greatest injustices in the history of the planet: of current adult generations to young people and future generations, and of people of the industrialized North to people of the South, as climate change is due mainly to emissions from nations at middle and high latitudes.

My preference would be to just remove the word “highly” from the title, i.e., replace “highly dangerous” with “dangerous ”, thus making the title slightly shorter and less “journalistic’, which was a concern of at least one referee. However, I understand that some scientists consider that title to be too definitive, so in hopes of avoiding delay in publication we have chosen “ Ice Melt, Sea Level Rise and Superstorms: Evidence from Paleoclimate Data, Climate Modeling, and Modern Observations Implies that 2°C Global Warming Above the Preindustrial Level Would Be Dangerous ”, which has been suggested as a possible compromise. I hope that you agree that our proposed alternative phrasing for the title is well motivated.

and, of course, the editor, Frank Dementer, has the final word

following a discussion with the ACP editorial board, I will request one
change in the title. In order to bring out even more clearly the element
of uncertainty associated with the work to change the word would into
could.

The title would thus become:
"Ice Melt, Sea Level Rise and Superstorms: Evidence from Paleoclimate
Data, Climate Modeling, and Modern Observations Implies that 2°C Global
Warming Above the Preindustrial Level Could Be Dangerous"

Whilst I disagree with TLE on the feasibility of extraterrestrial survival of terrestrial ecosystems or populations of any significance, I completely agree with him on the nature of the impending smack that humanity is delivering to the planet. Couching the science in timorous language does no one any favours: we need to wake up now, given the almost complete lack of action that has followed AR4, AR5, Obama's Nobel, Francis' excellent encyclical, and the all-wrapping-and-no-meat that was COP21.

Every week that has followed since Paris should have been filled with the latest news that signaled substantive changes to the way that countries energise themselves, and conduct their affairs. There's been nothing at all that remotely resembles the sort of action that was* needed to achieve the 2°C plateau, and certainly nothing that could ever have come within a bulls' roar of 1.5°C.

If science can't make the case now, at midnight, to ears that have already heard but haven't listened, then we might as well pack up and watch the unfolding destruction of our ecosphere knowing full-well that we simply didn't have the gumption to do anything about it, even though we understood the consequences of humanity's actions.

[*I use the past tense because I cannot see any real path from here to achieving less than a 2°C plateau, and probably not much below 3°C at least, if reality is faced...]

You don't seem to understand what I am saying Bernard. Extraterrestrial space development, settlement and colonization will get NOAA and NASA back on track to develop and deploy the new technologies we will need to solve these problems. We really don't need to study this problem any longer, just like we don't need to do more endless Mars and outer planet missions, we just don't need that data anymore, it no longer has no intrinsic value. That era is over.

What we need to do, is deploy large space telescopes where we can just look at those planets, and a million or so other planets, terrestrial and otherwise, and these things by definition have to be either solar or nuclear powered. And we need to have the knowledge to close up our own leaky life support systems right here at home.

But perhaps the biggest thing we need to do is give billions of people short rides in space, just like we do with airlines 100 years after air travel was invented, so they can see our planet as it is.

That more than anything will move the technologies we need forward.

Do you get it now? Somehow, I doubt it. It would help if you read up on the peer reviewed space cadet literature, and suffice it to say I am the most feared, reviled and respected space cadet on the planet.

I'm kind of thinking Hansen is reticent. After all, the title of said reticent paper includes in the title itself the 'weasel word' "could" ...

So "global warming is highly dangerous" morphed into "Implies ... Global Warming ... Would Be Dangerous" morphed into "Global Warming Could Be Dangerous" morphed into it's final form of "global warming could be dangerous" ...

Correct tile:"Ice Melt, Sea Level Rise and Superstorms: Evidence from Paleoclimate Data, Climate Modeling, and Modern Observations Implies that 2°C Global Warming Above the Preindustrial Level is very Dangerous, and very likely Catastrophic"

All other truthful titles involve substantial profanity.

All papers with more than 3 authors contain reticence which is proportional to the square of the number of authors. Consider for example, AR4's (2007) discussion of Arctic Ice. Part of this was delays due to communication overhead. Part of the communication overhead in this paper is understanding all of the unstated assumptions in the models.

I would be very surprised if weather projected for 2060 - 2080 does not occur in the next 30 years.

Journalistic, not scientific? I wouldn't know. So I searched in google scholar for titles with the word dangerous in them, solely in the Journal of Medicine.

275 results. That's not a lot. Quite a few were in quotes, others titles had a question mark at the end. But a few titles used "dangerous" similarly to the usage in Hansen et al' title. Perhaps if I checked the cite count for those....

Another search brought up a wee 2001 commentary in Nature by Stephen Schneider, who is quasi-famoulsy quoted about where to draw the line between messaging and accuracy in climate science communication. Wonder what he would have made of this kerfuffle.

I prefer to stay away from informal logical fallacies such as an appeal to authority.

Same goes to appeals to emotion, as Hansen has s-o-o-o-o-o-o-o-o got that one covered (e. g. court cases and zOMG think of the kids and grandkids).

Right now I'm much more interested in stuff like this ...

NOAA WAVEWATCH IIIhttp://polar.ncep.noaa.gov/waves/index2.shtml

... and this ...Smoothed-particle hydrodynamicshttps://en.wikipedia.org/wiki/Smoothed-particle_hydrodynamics#Uses_in_fluid_simulation

A conjecture HAS been 'floated' so to speak, that conjecture CAN be tested today. For the most part, using numerical models (some physical modeling would also help as a final step to confirm forcing mechanisms).

Applause to Bernard J and thanks to 8c77 for serving the paradigm of earth detached technofetishism we need to fight (i.e. ridicule ad nauseam). Maybe the time is coming to think rigorously about earth based solutions to the evil twin problems of the carbon cycle and hominin population overshoot? But last time I suggested the almost tautological solution the Archdruid JMG said this has to wait some centuries... The unbearable ridicu-lousiness of the Late Homo S Sapiens...

Yes sea level WAS higher and temperature WAS higher. However, AFAIK, we do need a better understanding of the natural causes leading to those specific conditions.

I call your argument the 'sameness fallacy' as in, because certain specific conditions or their final states, that may have been the same in the past, does not inherently guarantee that those same specific conditions today will lead to those specific conditions in the past.

See also: fallacy of composition, fallacy of the single cause, is-ought problem, retrospective determinism, hasty generalization, faulty generalization and the big one the association fallacy.

I call your argument the 'sameness fallacy' as in, because certain specific conditions or their final states, that may have been the same in the past, does not inherently guarantee that those same specific conditions today will lead to those specific conditions in the past.

Please list the laws of physics that have changed since the end of the Eemian.

If you can't think of any, then perhaps you are mistaken to assert that:

Exact same laws of physics, just, you know, different boundary conditions different forcings etceteras at that time, that have not been determined to date AFAIK.

The oceanic circulations/mixing and ice sheet dynamics are the climate scientists Achilles Heel, so to speak.

Now, I must be off so that I can make a list of evidence from the Hansen16 paper, with respect to superstorms (sea level highstands/rates, in and of themselves don't count). If the only answer they have is Bahamas, that's would appear to be a particularly weak line of evidence.

Exact same laws of physics, just, you know, different boundary conditions different forcings etceteras at that time, that have not been determined to date AFAIK.

I don't think you have a physically plausible argument here, EFS. Slightly different orbital dynamics to the Holocene meant GAT was a bit higher in the Eemian. This melted slightly more ice from the GrIS, WAIS and bits of the EAIS. Contributions to the ~6m Eemian SL are thought to be roughly 2m from the GrIS, 3m from the WAIS and 1m from the EAIS.

Since the laws of physics have *not* changed since the Eemian, if we crank GAT up by 1C and keep it up SL will go up by about 6m. We can argue whether this will take three centuries or five and the difference between disastrous and catastrophic, but not about whether it will happen.

It's very much an open question, get back to me when you look (in detail) at the Exuma Island chevrons, Harvey Cay/Staniel Cay (that one is vectored right into the middle of the backside of Cat Island) etceteras in Google Earth Pro.

Note their orientations, their lengths, their elevations in front of Exuma Island. Do some elevation profiles even.

Now go to the main set of criss-crossing chevrons (23°36'58.79"N 75°55'46.31"W), near George Town, note the two crescent beaches (orientations, particularly the southern one) on either side of the headlands. Also note the chevrons in that particular spot, many lines, there are.

Now, to repeat what I said above, get back to me when you can demonstrate four decades of hydrodynamics experience (three of those decades in the hydrodynamics of water waves in the offshore-to-onshore coastal zone).

Conclusions? That has to be one heck of a storm surge, so much so, that it is highly unlikely to have been induced from long traveled NW swell. In fact, its right out of The Day After Tomorrow playbook, three gigantic Northern Hemisphere supercells AND that stuff has to get past the upwave direction topographic obstructions (draw some lines such that deep water waves have a clear access path, what get's past those topographic obstructions must also diffract and refract, both acting to diminish the subsequent onshore wave heights and I'm not aware of anything one would call deep water storm surge height).

I do want to know under what conditions the MIS-5e 6-9m highstand occurred (with respect to the current GMSL).

That's my entire point in me wasting my time discussing this with you.

I want to know WHY it was warmer at that time, I am not satisfied with +1C and +6-9m as the linkage between those two pieces of information or separate facts as they are not sufficient to answer the why-where-how question. I am looking for more information on both the RHS and the LHS sides of your overly simplistic "equation" with spatio-temporal independent variables even.

I need to understand, as best as I can, as I am a curious and inquisitive sort of person, others appear to just assume stuff using the sameness rubric, when sameness of some salient information is an incomplete answer IMHO.

Hansen16 short version is your simplistic "sameness" answer, that is ...

+1C = 6-9m SLR

It only took 19 authors and 67 pages of very questionable hand waving to say ...

+1C = 6-9m SLR

So that, in my case at least, I now know less than I did prior to Hansen's paper. I have had to question their interpretation of a rather small knowledge set. The more I look into their interpretation, the less I like their interpretation.

That this is ALWAYS subject to change (meaning my understanding) when new information or existing information see's the light of day, be it paleo or observational or numerical.

Then read a bloody textbook. Orbital dynamics: higher eccentricity and increased precessional forcing resulted in elevated NH summer insolation relative to the Holocene. The rest was feedbacks, mainly albedo and GHGs. This melted more ice than Holocene climate and raised MSL by about 6m. It's this basic: heat melts ice. The geode has sod-all to do with MSL differences between the Eemian and the Holocene. Go find a reference that says it does if you are going to peddle this stuff. Otherwise, concede the point. This is tedious.

EFS - the Bahamas chevrons are indicative of the prevailing winds at time of creation. There is no evidence for a tsunami in the Bahamas during MIS5e. If you believe there is such evidence, why not point to it?

In fact, your analysis would involve *multiple* tsunamis - not just one. While the compass vector for prevailing winds can change significantly over small geographic distances - accounting for chevrons that are not all the same direction -- a tsunami would create chevrons that are all basically perpendicular to the source. And of course no source for these proposed tsunamis has ever been shown.

EFS, can you identify which X you think relate to dh? The Eemian was 130,000 to 115,000 years ago, so continental drift can't have been a big factor, ditto the shape of the geoid. But perhaps there are other factors I'm not aware of. Excursions in salinity would perhaps affect the density of the ocean, and such might come from different freshwater/saltwater mixes. Do you have some theory that can account for the 7.5 m rise in sealevel with 1 K rise in mean global annual surface temperature? I mean, do you have a more sophisticated model than "there might be other factors?"

"Someone [Hansen] is getting very old, that someone has gone emeritus, that someone so desperately wants humanity to do something before they die, that someone will surely die very unhappily at what humanity has, and has not, done. Those are the basic cold hard facts that I understand them.

Just about every EFS comment in that thread contains a condemnation of the Hansen et al paper. Nothing has changed except his memory of events.

Hand waving. Point me to the relevant peer reviewed literature. A 6-9m highstand does change the geoid. Otherwise ... heck I don't know ... but I'm not staying around for one of your endless discussions ... that's for sure. All you are doing is stating bog standard stuff and MIS-5e, according to Hansen16 does not appear to be bog standard stuff (e. g. the temporal rate of SLR).

Kevin O'Neill,

It's an open question. I don't have a specific answer at this point in time. It would appear that no one else does either. I stated p > 0.5 (e. g. almost equal probability). My 'analysis' doesn't incorporate a whole lot at this point, the only thing 'almost' off my table, so to speak, are Hansen's and Haerty's assertions/conjectures with respect to super-mega-storms.

You do really need to get with my thought train (or not, I really don't care), numerical modeling to test potential forcing mechanisms. This is something that the USACE ERDC CHL does all the time (e. g. NAD or North Atlantic Division, Hurricane Sandy type stuff). It's something that Philip L-F. Liu and many other academics do all the time (Hansen and Hearty are MIA in that department, that's for sure).

Heck, right now I'm thinking hurricanes. You really should look into what a coastal study involves, as in, we don't do interpretive studies (well, at least groups that would numerical and physical modeling), wave heights prescribed, wave directions prescribed, water levels prescribed, baseline conditions prescribed, etceteras. SOP type stuff.

In other words, stop building strawmen about tsunamis, that's only one possibility (e. g. absence of evidence is not the evidence of absence, appeal to ignorance).

At least one study needs to be done, as of right now, zero studies have been done (that IS the beauty of Hansen16, to spur on future efforts, by SME's in other fields of expertise).

BPL,

PDE's if you don't mind. If not, that than additional paleo data, if possible, to help nail down, add to, the temporal aspects and water levels more accurately around MIS-5e.

Kevin O'Neill,

Actually, my memory is quite good, whatever I said then I said then, whatever I say now I say now.

I do know that I deleted a whole bunch of stuff right around the time BP was here. Why? I made the most offensive statement to BP that I could think of at that time. I thought for sure that that would ban-me-for-life at RR, so I went back and deleted all comments from the start of the rather short lived BP era. I do save all comments though before posting, sort of like "note to self" text files.

But if you still haven't figured it out, I am on a learning curve, Hansen16 is a very thought provoking paper. But I need to do more then just think or talk about the paper, I need to understand the paper and that requires further prior art and lay-of-the-land research to somewhat satisfy my curiosity.

EFS, partial differential equations are superior to algebra how, exactly? It's important what the various derivatives are? Why? I don't get that. If you want to phrase your model in terms of PDEs, go for it. I have yet to see any particular mathematical model from you, just a dismissal of BBD's model.

The volume of grounded ice on Earth is 2.934 x 10^16 m^3. The melting of 7/61 of this releases 3.37 x 10^14 cubic meters. Since fresh water is denser than ice by a factor of 1000/917, this becomes 3.09 x 10^15 m^3.

Earth's total area is 5.10066 x 10^14 m^2, of which 70.8% is water (Sellers 1965, p. 5). Thus, spread out over the ocean, the new ocean height rises 8.56 meters, and spread out over the whole globe, 6.06 meters. Hansen et al.'s figure is thus just in the ballpark of what it should be.

Hart MH 1978. The Evolution of the Atmosphere of the Earth. Icarus33, 23-39.

Sea ice covers 3.59% to 3.82% (the difference is due to the ~37 year global anomaly trendline, 1979-01-01 thru 2016-03-24) of the Earth's surface based on the UIUC dataset available here ...http://arctic.atmos.uiuc.edu/cryosphere/timeseries.global.anom.1979-2008

Total land and sea ice = 2.89% + 3.59% = 6.48%

Not much that I can to say at this point, except that one should not use an equation that includes sea ice area to infer sea level rise which can only come from that 2.89% fraction that is land ice.

Heck, the 0.23% difference for total ice cover produces (working backwards from the equation) only a 0.28C temperature rise in 37 years or 0.28C/0.37 centuries is only 0.75C/century.

I'm not using the dynamic geoid to explain SLR, it might change the Earth's polar moment of inertia (RE: Chandler Wobble and/or insolation). Most probably not a factor.

It has been said that the MIS-5e stage highstand happened rather rapidly, in the geological sense, or in the sense of current GMSL to +6m to +9m is a very short timespan (decadal to centennial). So like the chicken and the egg, which came 1st or in tandem, the slowdown/stopping of the MOC overturning circulation, etceteras.

IMHO, there are knowledge gaps, +1C and +8m to +9m, in and of themselves, do not completely satisfy my inquisitive nature.

It has been said that the MIS-5e stage highstand happened rather rapidly, in the geological sense, or in the sense of current GMSL to +6m to +9m is a very short timespan (decadal to centennial). So like the chicken and the egg, which came 1st or in tandem, the slowdown/stopping of the MOC overturning circulation, etceteras.

The key point is that this is evidence for ice sheet instability not currently captured by ice sheet models.

"The key point is that this is evidence for ice sheet instability not currently captured by ice sheet models."

You mean they are left with hosing the Arctic and Antarctica?

That's so The Day Before Yesterday.

Oh wait, zOMG, you mean they have to tune the ice sheet models based on +1C = 6-9m SLR. Because ... wait for it ... Hanses sez so.

This stuff is s-o-o-o-o-o-o-o-o-o TBD, you need to get past that one basic fact.

Until MIIS-5e is actually modelled in some fashion bolstered by significantly more paleo evidence, we are left with hosing the oceans in a completely arbitrary capricious random anything goes manner. Curve fitting.

To be clear, I am not specifically defending Hansen16. I'm objecting to the blurred lines between pissing on Hansen because whatever and the facts, which are simple enough: centuries of rapid sea level rise are very likely unless less CO2.

The paper is broad and wide, and it would have much more to do with those papers themselves than in the Hansen16 interpretation of those and many other papers not referenced in Hansen16. I've seen too much cherry picking in the technical literature (meaning in climate science and in my field), in order to buttress one's point, particularly when they become overly interpretive, which is my current read on Hansen16.

That does mean something like a Google Scholar search for other papers not referenced in Hansen16.

But I've been rather busy on the boulders and causation mechanisms thereof. I have at least a month worth of reading in that Google Scholar search area alone. Long story short? It is very complicated, as in there does not currently appear to be a consensus, mainly because the coastal conditions and deep water to shallow water hydrodynamic mechanisms vary greatly.

EFS writes: "...we are left with hosing the oceans in a completely arbitrary capricious random anything goes manner ..."

Which, of course, bears little resemblance to the actual paper: "We add freshwater to the North Atlantic (ocean area within 52–72◦ N and 15◦ E–65◦ N) or Southern Ocean (ocean south of 60◦ S)"

Translating this onto a map (Fig. S13 in the supplement to the final paper), the water is injected at the glacier outputs around Greenland and at various points along the Antarctic coast. So much for arbitrary and capricious. EFS, I thought you read the paper?

"To be clear, I am not specifically defending Hansen16. I'm objecting to the blurred lines between pissing on Hansen because whatever and the facts, which are simple enough: centuries of rapid sea level rise are very likely unless less CO2."

Yes, I think there will be several meters, WAIS and Greenland.

Speaking as a coastal engineer (or civil engineer) I see dangerous coastal engineering structures being built, a slippery slope so to speak, due to the current rather tepid GMSL rise rate, you build to +1m and once it reaches +1m you build to +2m or +3m (e. g. say NYC). Rince and repeat.

It's like New Orleans on steroids. Miami has already invested something like $300m in just pumping and drainage infrastructures. Nuisance flooding.

You temporarily disappear the nuisance problem, then a minor hurricane hits, and it's onto dikes and levees and seawalls, not unlike what you see what the Netherlands has done to date, because the local interests demand such (politically real estate interests).

We have the continental shelves and very low coastal relief ...http://www.ngdc.noaa.gov/mgg/coastal/crm.html

How many major population centers does the USA have on the Atlantic and Gulf seacoasts? It appears to me that we will build that many Netherlands. :(

"Which, of course, bears little resemblance to the actual paper: "We add freshwater to the North Atlantic (ocean area within 52–72◦ N and 15◦ E–65◦ N) or Southern Ocean (ocean south of 60◦ S)"

Translating this onto a map (Fig. S13 in the supplement to the final paper), the water is injected at the glacier outputs around Greenland and at various points along the Antarctic coast. So much for arbitrary and capricious. EFS, I thought you read the paper?"

Like rivers to the sea, it is not.

Like ocean waves passing floating ice blocks, with very much turbulence to be had, it is not.

Large eddy resolving resolution, it is not.

I never used the word 'hosing' until WC and PT used it, but it is a useful meme, as it were.

The ice calving and fresh water releases occur at the SHORELINE, oh please, oh pretty please, put it where it is most likely to originate (look at what the USACE did for the NAD, that's the type of grid resolution coastal types use).

Oh wait, you said they did, but wait a four DEGREE horizontal resolution grid. Help me out, what's the vertical resolution? Q = VA, so the velocity is divided by the cell width and the cell height, go figure, please?

"All of these modifications tend to increase the ocean stratification, and in particular the Southern Ocean state is fundamentally improved. For example, we show in Sect. 3.8.5 that our current model produces Antarctic Bottom Water on the Antarctic coastline, as observed, rather than in the middle of the Southern Ocean as occurs in many models, including the GISS-ER model documented in CMIP5. However, although overall realism of the ocean circulation is much improved, significant model deficiencies remain..."

Now, when one is questioning the validity of over-turning currents, you might expect one to use a model that gets the bottom water formation location correct. Hansen's does.

As for, "As a research hydraulic engineer I laugh in their faces." Are we, am I, supposed to be impressed? Guess what? I'm not. Shall we start referring to you as Chief Hydrologist per the nutcase at Curry's?

"Was your characterization of the inputs as arbitrary and capricious correct?"

Yes, more so then even I expected.

The paragraph you quote sounds exactly like model 'tuning' and well, words in and of themselves, mean nothing.

"Now, when one is questioning the validity of over-turning currents, you might expect one to use a model that gets the bottom water formation location correct. Hansen's does."

You are the trusting sort of chap, I see. Me not so much, it is in my nature. I would need their datasets and available prototype datasets to make that judgement call. Is Hansen suggesting that all OTHER models are wrong except his, and if so, under what objective basis. Note to self: Someone proclaiming goodness of fit will likely only mention the good fit and remain silent or reticent on the bad fits.

EFS - they specifically inject the water at the outlets of the Arctic and Antarctic glaciers. You call this arbitrary and capricious. Excuse me - where else is the land-ice freshwater going to come from? Magic freshwater ice-fairies? Sorry - end of discussion. That is Goddard level dumb and your doubling down on it only makes you look like a Goddard-level dumbass. Chief Hydrologist you are.

EFS,I would like to hear your response to this from Hansen et al on hydrodynamic modelling of boulder tossing

The inadequacy of hydrodynamic modeling of boulder movement is shown by observations of large storm-tossed boulders. North Atlantic storms threw boulders as large as 80 tons to a height 11 m AHWM (above high water mark) on Ireland’s Aran Islands, this specific storm on 5 January 1991 being driven bya low pressure system that recorded a minimum 946 mb (equivalent to a category 3 hurricane). Winds gusted to 80 knots and the closest weather station to the Aran Islands recorded gale force winds for 23 hours and sustained winds of 40 knots for five hours [Cox et al., Boulder ridges on the Aran Islands(Ireland): Recent movements caused by storm waves, not tsunamis, J. Geology, 20, 249-272, 2012]. The storm waves built onto swell that was developed by strong winds during the prior two weeks. Cox et al. (2012) note that existing hydrodynamic modeling equations would not lift the boulders, andthey cite two reasons to disregard the equations. First, wave height measurements reveal that waves twice the SWH (significant wave height) of models frequently occur. Second, existing wave equations do notinclude effects of reflection from cliff and shoreline, and attendant wave amplification. Cox et al. note that wave heights at shoreline cliffs can be much greater than the equilibrium height of approaching deep-water waves. The waves steepen as they shoal, impact the coast, reflect back, meet advancing wave crests causing a mixture of constructive and destructive interference, with intermittent production of very large individual waves capable of quarrying and transporting large blocks and boulders.These considerations also help explain why megaboulders (~1000 tons) on Eleuthera are only found just south of Glass Window Bridge at the apex of an embayment that funnels waves before they encounter a steep shoreline cliff (Figs. 1-3 of Hearty, P.J., Quatern. Sci. Rev., 17, 333-355, 1998; also Hearty, P.J., Quatern. Res. 48, 326-338, 1997).

There are no hydrodynamic SME's anywhere's in that paper, that's a definite FACT!

I don't use the word liars, but when I do, I do so often.

That's coming from Hearty, and he is in the wrong field, what he does write is baby talk, for anyone that does serious modeling in the coastal zone. That includes physical modelling, at say OSU's tsunami facility (it is actually a really big wave basin), been there, done that.

EFS, i am not following you argument as it relates to the modelling. are you saying that the various methods you outline(RANS, Boussinesq, PSH and LMCS) do an effective job of modelling boulder transport. do you have any references i might investigate?

if i may quote directly from Cox et al 2012 :

Difficulties of Using Wave Equations to Draw Conclusionsabout Boulder Transport in Coastal Settings.

Wave-transport equations (especially those of Nott2003a, 2003b) have been used as a cornerstone ofthe argument that the Aran Islands boulders cannotbe storm deposited. Scheffers et al. (2009, 2010a)posit an upper limit of 10–20 m3 (26–52 t at 2.6 t/m3) for storm-wave boulder movement, and althoughthe vast bulk of the Aran Islands ridges aremade of clasts well below that mass (table A2), theridges contain many clasts that are much bigger(e.g., table A5). Therefore, argue Scheffers et al., theAran Islands ridges must be tsunamigenic.We disagree. The reasoning by Scheffers et al.(2009, 2010a) assumes that the Nott (2003a, 2003b)equations fully describe wave behavior at the coast,but this is not in fact the case. Morton et al. (2008)point out that although the Nott equations havebeen commonly used as evidence for tsunami emplacementof large clasts, “there is a clear need forevaluating the basic assumptions of the equationsand applications of the results” (p. 636). The Nottequations—and recent updates by Nadesna et al.(2011)—are a valuable tool for thinking about wavedynamics and have helped us wrestle with the problemsof block transport, but they represent a simplemodel of progressive wave motion. Important variablesare not considered, including nonuniformcoastal slopes and foreshore bathymetry (Kelletat2008). It does not seem that the equations can beapplied in the case of very steep, stepped, or cliffedcoasts, such as those that prevail in the Aran Islands,and they do not account for wave-modifyingeffects, such as reflection and constructiveinterference.The physical experiments of Hansom et al. (2008)show the complex behavior that results when wavetrains impact a cliff wall. Because the cliff modifiesthe behavior of the leading wave and causes it tofall back and interact with the successive waves inthe train, even waves that break below the cliff topcan generate overtopping bores that inundate thecliff-top ramp with high-velocity flow. Hu et al.(2000) have pointed out that “wave overtopping isa complex phenomenon to model. It involves waveshoaling, wave breaking, wave reflection, turbulenceand possibly wind effects on water spray.Because of wave reflection, the complex nature ofrandom waves is an important factor in wave overtopping.Unsurprisingly therefore, the accurate numericalmodeling of wave overtopping is a very dif-ficult task” (p. 434).

Back in dem dare olde tyme days, there were two types of linear water wave models, parabolic and elliptic, parabolic could not solve the backscatter problem while elliptic could.

But that's s-o-o-o-o-o-o-o-o-o-o-o 30 years ago. No one that I'm aware of, for phase resolving deterministic wave models, solves the parabolic form of the various water wave equations. If they are, then they should shoot themselves in the head.

Yes, I have tracked down about 100 references. PSH is going gang busters right now, it use to be RANS (6.1 monies in military lingo a decade ago), Boussinesq about two-three decades ago.

The best that I could do is zip them up and put them on Google Drive.

I would rather suggest an exhaustive search for boulder papers, storm surge or tsunami related, there has been a lot of work done recently. There currently is no definitive answer, it could be either, it does very much depend on the nearshore environment though.

Her critique is the only real reason to run a physical model, however, the PSH has been used as it can do wave overtopping and rundown.

Some people do take this stuff rather seriously, interpretive types not so much.

Cox has no 1st hand experience in hydrodynamics, she is just reading other papers, and applying interpretations, she's a geologist after all.

This whole issue needs a LIDAR survey (nearshore high resolution bathymetry that the USACE does all the time) and the latest generation of phase resolving numerical water wave models (nearshore). And a energy based non-phase resolving water wave model such as NOAA's WAVEWATCH III (which I'm told that the USACE ERDC CHL is transitioning to, plus I have a requested version (nothing special about having a copy though)).

Here's an interesting one. I got these figures from a geologist on an amazon board. I do NOT have primary citations for any of these yet, though I'm searching. If, and only if, these figures are valid, there are interesting implications.

I don't know if I could present a coherent single page (or two) write up.

It would take me some time, much more so then most people, that is my Achilles Heel, so to speak.

My overall written skills are not the best, it takes me 10X the time of those like you or WC or Sou, or heck, about 90% on humanity.

That die was cast in my youth, very poor spelling and poor grammar, plus my clinical anxiety with respect to work related deadlines.

I must admit, that after yesterday's efforts, I had pushed my own limits to the brink of "why don't I just STFU' that was my thought process this morning, basically just give it a rest.

For whatever reasons, I think my overall technical view happens to be very close to PT's technical view, at least with respect to exponential SLR and superstorms, his writing skills are 100X my writing skills (mainly because he does not get bogged down in endless details as I am very apt to do).

I have tried to read various portions of Hansen16 several times now and I find myself getting bogged down in it's IMHO overly referential nature (things that I don't understand or doubt causes me to chase down those references and/or other references).

I think that whatever I would write would be longer than Hansen16 and that that, IMHO, is not a good thing.

EFS:"My overall written skills are not the best, it takes me 10X the time of those like you or WC or Sou, or heck, about 90% on humanity."

Everett, if you're fishing for compliments, I'll bite. Your posts on RR are usually written rather well. Your spelling and grammar, at least, aren't a problem.

One thing I've learned by hanging out on blogs in the last 10 years: one's writing skills can be expected to improve with practice, but for most of us, writing anything our target audience will take the trouble to read will always be hard work.

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Eli Rabett

Eli Rabett, a not quite failed professorial techno-bunny who finally handed in the keys and retired from his wanna be research university. The students continue to be naive but great people and the administrators continue to vary day-to-day between homicidal and delusional without Eli's help. Eli notices from recent political developments that this behavior is not limited to administrators. His colleagues retain their curious inability to see the holes that they dig for themselves. Prof. Rabett is thankful that they, or at least some of them occasionally heeded his pointing out the implications of the various enthusiasms that rattle around the department and school. Ms. Rabett is thankful that Prof. Rabett occasionally heeds her pointing out that he is nuts.